The UK's only Chinese-born parliamentarian last night challenged police and community leaders to defend a mixed-race couple targeted by neo-Nazis in Northern Ireland.

Anna Lo, an anti-racist campaigner and member of the Northern Ireland Assembly, condemned arsonists who set fire to the family's home in Ballyclare, Co Antrim, early yesterday.

It is understood the couple had been subjected to a race-hate campaign in the town over the last few months. Lo said that, if the victims of the attack wanted to stay in Ballyclare, the police and the local community should publicly rally around them.

"If they wish to stay in the town after this dreadful incident, it is up to the police and local people to stand by them, to prevent them from being intimidated out of Ballyclare," she said. "Because to do nothing could hand a victory to these racist thugs."

The South Belfast MLA and Alliance Party member added: "These neo-Nazi groups do exist in Northern Ireland and the time has come to root them out. In our new society these are the last people we need organising and spreading their message of hate around." She called for more to be done to counter the groups, which she said had been recruiting in loyalist areas over the last few years.

"It is terrible that this couple were targeted, because the woman was from the Indian community. Indian people have lived and worked in Northern Ireland for decades. They have contributed to the business and social life of the province. They have brought a great deal to our society, unlike those behind the attack in Ballyclare, who have absolutely nothing to offer," she added.

A PSNI spokeswoman said that the two downstairs windows in the Ballyclare house were smashed soon after 5am yesterday, and a container of blazing flammable liquid thrown in. One of the householders fought the fire and managed to extinguish it before the fire service arrived. The couple were said to be uninjured but shaken by the incident, which police are treating a racist attack.

The father of the male victim criticised the PSNI's handling of the situation. Speaking yesterday from New Zealand, former police officer John Bowler said: "This was preconceived. They had to think about getting a breeze block and petrol. I would describe the attack as attempted murder."

He added that his son, and his wife Ajita, had been the targets of repeated racist abuse in Ballyclare, which the PSNI knew about.